This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Hypothesis: The antitumor effects of ON 01910.Na on a broad spectrum of tumor cell lines in culture and animal models, including many drug resistant cell lines, and its high therapeutic index, provide a strong rationale for clinical studies in the treatment of cancer patients. This study is for patients who have a diagnosis of an advanced cancer, which cannot be cured with present knowledge and for which no other therapy is known to be consistently effective. This research study will use ON01910.Na, a new anticancer agent, which is investigational (has been approved by the Food and Drug Administration for study but not for sale). This is an open-label, dose-escalating Phase I study of ON 01910.Na in ambulatory patients with advanced cancers, who have satisfied the inclusion/exclusion criteria enumerated in this protocol. Patients will receive ON 01910.Na intravenously by 3-day continuous infusion every 2 weeks, until evidence of disease progression, specific adverse events quantified by an established scale of the National Cancer Institute to reach a level of grade 3 (out of 4) in two patients in a cohort of 4 to 6 patients, or withdrawal of patient consent. After the Recommended Phase II Dose has been determined, up to an additional 12 patients may be added to confirm the appropriateness of the Recommended Phase II Dose. This regimen of a 3-day continuous infusion every 2 weeks, is an interesting and appropriate alternative dose regimen to the 2-hour, twice a week infusion schedule for 3 weeks with 10 days recovery, that is currently under investigation under a different protocol (04-01) at The Johns Hopkins University Oncology Center. Five patients have been studied for up to six doses. The only toxic side effect that has occurred was grade 1 diarrhea in one patient (possibly drug related).